1. Technical Field
The present invention relates generally to footwear and, more particularly, to a footwear sole to which a spring is attached, thus contributing to realizing the remedy, prevention and treatment of musculoskeletal disorders.
2. Background Art
Footwear which is a necessity of daily life has been designed to be suitable for special purposes or developed to have various additional functions, in addition to the original function of simply protecting the feet.
A variety of footwear which is used for games or medical treatment has been known to people. As one example of the footwear, US Publication No. 2007-0180773-A1 has been proposed, which was filed by the same inventor (Eun Jae Lee) as the present invention and entitled “shoe sole for correcting gait”.
FIG. 1 is an exploded perspective view illustrating the important parts of the conventional footwear sole for correcting gait.
As shown in the drawing, the conventional footwear sole includes a main sole 100, an auxiliary sole 200 and a coupling seat. An upper 400 is coupled to the upper portion of the main sole 100, thus forming the footwear. Especially, the main sole 100 is divided into a front midsole 110 and a rear midsole 120 which are coupled to each other. The front midsole 110 is made of a soft material, while the rear midsole 120 is made of a hard material. The auxiliary sole 200 is coupled to the rear midsole 120. To this end, a flat coupling seat is provided on the lower surface of the rear midsole 120, and a connection member is coupled to the top of a coil spring which is included in the auxiliary sole 200. The rear midsole 120 and the auxiliary sole 200 are fastened to each other by fitting a bolt into the connection member. For the coupling of the connection member with the coil spring, the connection member is integrally provided on the top of the coil spring through injection molding.
However, it is very difficult to manufacture the connection member as described above. Further, there are many restrictions on mass production. Further, a person may have the left and right legs which are considerably different in length from each other. In this case, footwear which is capable of solving a user's congenital or postnatal problem is required.